Narrative:

After IFR flight plan departure from rno, we flew the mustang departure under VOR navigation. Left seat (PF) was 26 yr old ATP, 3000 hours total time, with experience in kingairs. We were given a change in clearance restricting interim climb to 15000 ft MSL by holding at 10000 ft MSL. I was in the right seat acting CFI-mia (time in type 6000 hours), and I reset altitude alerter back to 10000 ft. Per airline procedures, I pointed to the alerter and asked her to verify the new assignment, which she did. Since the current leg to redding (rdd) has no victor airway, I had my head down, looking at the LORAN display while I set in the new route and configuring her HSI display with cursor and CDI settings. The controller then stated for us to check our altitude, which read about 10450 ft MSL and climbing! I took control of the airplane and returned to the assigned altitude she had confirmed, but not realized the information. Since we were off-airways at the time, there was no traffic nor any hazard since WX was cavu.

Google
 

Original NASA ASRS Text

Title: ALTDEV ALT OVERSHOT.

Narrative: AFTER IFR FLT PLAN DEP FROM RNO, WE FLEW THE MUSTANG DEP UNDER VOR NAV. L SEAT (PF) WAS 26 YR OLD ATP, 3000 HRS TOTAL TIME, WITH EXPERIENCE IN KINGAIRS. WE WERE GIVEN A CHANGE IN CLRNC RESTRICTING INTERIM CLB TO 15000 FT MSL BY HOLDING AT 10000 FT MSL. I WAS IN THE R SEAT ACTING CFI-MIA (TIME IN TYPE 6000 HRS), AND I RESET ALT ALERTER BACK TO 10000 FT. PER AIRLINE PROCS, I POINTED TO THE ALERTER AND ASKED HER TO VERIFY THE NEW ASSIGNMENT, WHICH SHE DID. SINCE THE CURRENT LEG TO REDDING (RDD) HAS NO VICTOR AIRWAY, I HAD MY HEAD DOWN, LOOKING AT THE LORAN DISPLAY WHILE I SET IN THE NEW RTE AND CONFIGURING HER HSI DISPLAY WITH CURSOR AND CDI SETTINGS. THE CTLR THEN STATED FOR US TO CHK OUR ALT, WHICH READ ABOUT 10450 FT MSL AND CLBING! I TOOK CTL OF THE AIRPLANE AND RETURNED TO THE ASSIGNED ALT SHE HAD CONFIRMED, BUT NOT REALIZED THE INFO. SINCE WE WERE OFF-AIRWAYS AT THE TIME, THERE WAS NO TFC NOR ANY HAZARD SINCE WX WAS CAVU.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.